In the mobile communication system such as a mobile phone system, access networks for connecting radio base stations are constructed. The access network using radio communication by means of microwaves has the advantage of low network construction costs and flexibility in terms of where radio base stations can be installed. The radio communication equipment for constructing an access network of this kind includes: an antenna apparatus installed at an obstacle-free, high elevation place such as a steel tower, the roof of a building; a radio communication apparatus installed close to the antenna apparatus; and an indoor apparatus that is separated from these and installed indoors to perform modulation and demodulation processing of transmission signals.
The antenna apparatus and the radio communication apparatus send and receive high-frequency signals via a waveguide. Specifically, a waveguide portion provided for the antenna apparatus and a waveguide portion provided for the housing of the radio communication apparatus are aligned opposite to each other and are closely joined to form a waveguide, through which high-frequency signals propagate. However, if there is a gap between the waveguide portion of the antenna apparatus and the waveguide portion in the housing of the radio communication apparatus, high-frequency signals leak out of the waveguide from the gap, resulting in signal loss when high frequency signals are propagated.
To deal with this, in the configuration described in Patent Document 1, a slidable shim is disposed at the joint between the waveguide portion of the antenna apparatus and the waveguide portion in the housing of the radio communication apparatus. Thus, the waveguide portion of the antenna apparatus and the waveguide portion in the housing of the radio communication apparatus are connected by the shim so as to construct a waveguide without a gap.